High pressure pump rod packing assembly



May 25, 1965 w. M. HAESSLER 3,185,487

HIGH PRESSURE PUMP ROD PACKING ASSEMBLY Filed March 7, 1963 F '1' F 5 WALTERINP'IITEIITIZESLER I ATTO R N EY United States Patent 3,185,487 HIGH PRESSURE PUMP ROD PACKING ASSEMBLY Walter M. Haessler, Chatham, N.J., assignor, by mesne assignments, to Fire Equipment Manufacturing Corporation, New York, N.Y., a corporation of Delaware Filed Mar.7, 1963, Ser. No. 263,461

7 7 Claims. (Cl. 277--20) The present invention relates to high pressure gas pumps and more particularly to a pump rod packing as sembly for such pumps.

In the use of high pressure carbon dioxide and other gases it is customary to ship the gas in large containers to service stations where the gas is transferred to smaller containers for consumer use.- In the case of carbon dioxide the gas is generally maintained under sufficient pressure to be in the liquid form. and it is generally charged into the small containers by the use of reciprocating transfer pumps in which both sides of the piston are used for the pumping action. Difficulty has been had with prior constructions in maintaining the pump rod packing assembly sufficiently leak proof to prevent the loss of gas et without producing excessive friction. In the event a leak develops in a pump rod packing assembly transferring carbon dioxide, the carbon dioxide expands towards atmospheric pressure and at the same time drops to 70 to 110 degrees F. below zero. Carbon dioxide ice is formed in the leak and prevents the leak from becoming self sealing. Contact of the carbon dioxide with the pump rod causes the condensation of atmospheric moisture on the pump rod resulting in the formation of rime ice which abrades and rapidly destroys the packing. Thus it is important that any ice be prevented from forming because once present it is necessary to shut down the pump and allow it to warm up before the packing effectively can be tightened.

The present invention aims to overcome the ditficulties and disadvantages of prior constructions by providing an improved pump rod packing.

In accordance with the invention this is accomplished by providing an enclosure for the packing proper which may be adjusted as desired and which is so shaped as to compress the packing into even contact with the pump rod. The packing is a section of a tubular rod of Teflon, a polytetrafluor-oethylene product made by DuPont which is machined or molded to shape the packing enclosure. Additional means are provided for the lubrication of the rod by the use of a silicone fluid.

Another object of the invention is to provide a high pressure pump rod packing assembly which is simple and economical in manufacture, eflicient in operation and durable in use.

Other objects and advantages of the invention will be apparent from the following description and from the accompanying drawings which show, by way of example, an embodiment of the invention.

In the drawings:

FIGURE 1 is a vertical sectional view of a high pressure pump rod packing assembly in accordance with the invention.

FIGURE 2 is an enlarged sectional view of the retaining nut for the packing assembly.

FIGURE 3 is an end view corresponding to FIGURE 2.

FIGURE 4 is an enlarged side view of the packing.

3,185,487 Patented May 25, 1965 FTGURE 5 is an end view corresponding to FIGURE 4.

Referring to the drawings there is shown in FIGURE 1 a high'pressure pump rod packing assembly 1 in accordance with the invention and including a housing 2 having a packing recess 3 therein. A ring type retaining nut 4 is threadedly engaged in the wall of the recess as indicated at 5. The outer portion of the wall of the recess is threaded while its inner portion is made with a smooth surface 6. The housing 2 is made with an apertured wall 7 through which extends a pump rod or plunger 9.

The ring type retaining nut 4 is made with an outwardly flanged surface It) shaped for engagement by a tightening tool such as a plain round rod which may be engaged in radially extending holes or recesses 11. Alternatively, the flanged surface 10 might be provided with flat surfaces iior engagement by a wrench. Outer surface 12 of the retaining nut 4 is made with a smooth surface, an annular groove 14 extending therearound adjacent the innermost end of the nut. An O-ring seating gasket 15 is positioned in the groove 14. The wall of the out 4 is made with ample clearance from the apertured end wall 7.

The ring nut 4 has a tapered inner surface 16 extending from the flange Iti to its inner end, the included angle between opposite walls being approximately 14 degrees. Inwardly of the flange It) the inner surface of the nut 4 i made with an enlarged portion defining a lubricating packing recess 17 within which is received a felt washer 19. Ou-twardly of the recess 17, the inner surface of the nut 4 is still further enlarged to define a washer recess 20 within which. is received a backing washer 21. An annular extension 22 of the nut 4 extends outwardly-and is turned in to retain the lubricating felt washer 19 and the backing Washer 21 in position.

A packing 25 which is machined or molded from Teflon i positioned about the pump rod 9 and confined in the packing recess 3 by the retaining nut 4. The packing has an inner surface 2'6 to conform to the diameter of the pump, rod 9, its ends are flattened and its outer surface is tapered to conform to the tapered inner surface 16 of the nut 4. Any equivalent material to Teflon may b used for the packing 25. However, Teflon has been selected because of its low coemcient of sliding friction and because it remains flexible at the low temperatures involved of the order of over one hundred degrees F. below zero and it is chemically inert to the gases involved.

The retaining nut i is provided with an oil receiving groove 30 on its surface adjacent its threaded portion. Multiple oil passages 31 are provided leading from the oil groove 36 to the lubricating washer recess 17. For convenience in applying oil to the oil groove 30 an oil cup 32, may be provided leading through an oil passage 34 in the housing 2 to a position above the oil groove 31.

A preferred lubricant is Dow Corning DC-ZOO silicone uid. It is believed that in addition to providing a lubricating action, which probably is unnecessary with the Teflon packing, that the silicone fluid prevents the possible adherence of minute particles of ice to the pump rod and thus inhibits any tendency for the formation of rime ice with resultant damage to the packing.

While the invention has been described and illustrated with reference to a specific embodiment thereof it will be understood that other embodiments may be resorted to without departing from the invention. Therefore, the form of the invention set out above should be considered 3 as illustrative and not as limiting the scope of the following claims. I claim:

1. A high pressure pump rod packing assembly comprising means forming a packing recess, a pump rod extending through the recess, a retaining nut threadedly engaged in the recess and having a tapered inner surface, a Teflon packing compressed between the retaining nut and the pump rod, silicone lubricating oil storage means, and a silicone lubricating fluid saturated fiber washer in fluid communication with the lubricating oil storage means positioned about the pump rod outwardly of the Teflon packing.

2. A high pressure pump rod packing assembly comprising means forming a packing recess, a pump rod extending through the recess, a retaining nut threadedly engaged in the recess, a Teflon packing compressed between the retaining nut and the pump rod, and a felt washer impregnated with DC-200 silicone fluid positioned about the pump rod outwardly of the Teflon packing.

3. A high pressure pump rod packing assembly comprising a housing having a recess therein, means forming an apertured wall defining the bottom of the recess, the wall of the recess having a smooth surface in the portion thereof adjacent the apertured wall, means forming a threaded'surface outwardly of said smooth surface, a pump rod extending through the aperture in the wall, a retaining ring nut having a flanged end, means forming tool engaging surfaces on the flanged end, means forming a threaded surface on the outer wall of the ring nut adjacent the flanged end, the ring nut wall having a smooth surface inwardly of said threaded surface, means forming a groove about the smooth portion of the smooth wall of the ring nut, an O-ring positioned in said groove, the ring nut having a tapered inner surface flaring outwardly in the direction away from the flange, means forming an enlarged portion of the inner surface of the ring nut and defining a lubrication packing recess, a lubrication packing in said last-mentioned recess saturated with DC-200 silicone fluid, means forming a still further enlarged portion of the inner surface of the ring nut outwardly of said lubrication packing recess and defining a washer recess, and a Teflon packing having a passage therethrough receiving the pump rod, the ends of the packing forming flat surfaces, the outer wall of the packing tapered to conform to the tapered inner surface of the ring nut.

4. A high pressure pump rod packing assembly comprising a housing having a recess therein, means forming an apertured wall defining the bottom of the recess, the Wall of the recess having a smooth surface in the portion thereof adjacent the apertured wall, means forming a threaded surface outwardly of said smooth surface, a pump rod extending through the aperture in the wall, a retaining ring nut having a flanged end, means forming tool engaging surfaces on the flanged end, means forming a threaded surface on the outer wall of the ring nut wall having a smooth surface inwardly of said threaded surface, means forming a groove about the smooth portion of the smooth wall of the ring nut, an O-ring positioned in said groove, the ring nut having a tapered inner surface flaring outwardly in the direction away from the flange, means forming an enlarged portion of the inner surface of the ring nut and defining a lubrication packing recess, means forming a still further enlarged portion of the inner surface of the ring nut outwardly of said lubrication packing recess and defining a washer recess, a washer in the recess, the end of the ring nut turned in maintaining the Washer in the recess, and a Teflon packing having a passage therethrough receiving the pump rod, the ends of the packing forming flat surfaces, the outer wall of the packing tapered to conform to the tapered inner surface of the ring nut.

5. A high pressure pump rod packing assembly comprising a housing having a recess therein, means forming an apertured wall defining the bottom of the recess, the wall of the recess having a smooth surface in the portion thereof adjacent the apertured wall, means forming a threaded surface outwardly of said smooth surface, a pump rod extending through the aperture in the wall, a retaining ring nut having a flanged end, means forming tool engaging surfaces on the flanged end, means forming a threaded surface on the outer wall of the ring nut adjacent the flanged end, the ring nut wall having a smooth surface inwardly of said threaded surface, means forming a groove about the smooth portion of the smooth wall of the ring nut, an O-ring positioned in said groove, the ring nut having a tapered inner surface flaring outwardly in the direction away from the flange, means forming an enlarged portion of the inner surface of the ring nut and defining a lubrication packing recess, means forming a groove about the base of the flanged edge of the ring nut, means forming an oil passage through the Wall of the ring nut leading from said groove in the flanged edge to the lubrication packing recess, means forming a still further enlarged portion of the inner surface of the ring nut outwardly of said lubrication packing recess and defining a washer recess, and a Teflon packing having a passage therethrough receiving the pump rod, the ends of the packing forming flat surfaces, the outer wall of the packing tapered to conform to the tapered surface of the ring nut.

6. A high pressure pump rod packing assembly comprising a housing having a recess therein, means forming an apertured wall defining the bottom of the recess, the wall of the recess having a smooth surface in the portion thereof adjacent the apertured wall, means forming a threaded surface outwardly of said smooth surface, a pump rod extending through the aperture in the wall, a retaining ring nut having a flanged end, means forming tool engaging surfaces on the flanged end, means forming a threaded surface on the outer wall of the ring nut adjacent the flanged end, the ring nut Wall having a smooth surface inwardly of said threaded surface, means forming a groove about the smooth portion of the smooth wall of the ring nut, an O-ring positioned in said groove, the ring nut having a tapered inner surface flaring outwardly in the direction away from the flange, means forming an enlarged portion of the inner surface of the ring nut and defining a lubrication packing recess, a lubrication packing in said last mentioned recess saturated with DC- 200 silicone fluid, means forming a groove about the base of the flanged edge of the ring nut, means forming an oil passage through the wall of the ring nut leading from said groove in the flanged edge to the lubrication packing recess, means forming a still further enlarged portion of the inner surface of the ring nut outwardly of said lubrication packing recess and defining a washer recess, a washer in the recess, the end of the ring nut turned in maintaining the washer in the recess, and a Teflon packing having a passage therethrough receiving the pump rod, the ends of the packing forming flat surfaces, the outer wall of the packing tapered to conform to the tapered inner surface of the ring nut.

7. A high pressure pump rod packing assembly com-- prising a housing having a recess therein, means forming an apertured wall defining the bottom of the recess, the Wall of the recess having a smooth surface in the portion thereof adjacent the apertured wall, means forming a threaded surface outwardly of said smooth surface, a pump rod extending through the aperture in the wall, a retaining ring nut having a flanged end, means forming tool engaging surfaces on the flanged end, means forming a threaded surface on the outer wall of the ring nut adjacent the flanged end, the ring nut Wall having a smooth surface inwardly of said threaded surface, means forming a groove about the smooth portion of the smooth Wall of the ring nut, an O-ring positioned in said groove, the ring nut having a tapered inner surface flaring outwardly in the direction away from the flange, means forming an enlarged portion of the inner surface of the ring nut and defining a lubrication packing recess, means forming a still further enlarged portion of the inner surface of the ring nut outwardly of said lubrication packing recess and defining a Washer recess, and a Teflon packing having a passage therethrough receiving the pump rod, the ends of the packing forming flat surfaces, the outer wall of the packing tapered to conform to the tapered inner surface of the ring nut.

References Cited by the Examiner UNITED STATES PATENTS EDWARD V. BENHAM, Primary Examiner. 

1. A HIGH PRESSURE PUMP ROD PACKING ASSEMBLY COMPRISING MEANS FORMING A PACKING RECESS, A PUMP ROD EXTENDING THROUGH THE RECESS, A RETAINING NUT THREADEDLY ENGAGED IN THE RECESS AND HAVING A TAPERED INNER SURFACE, A TEFLON PACKING COMPRESSED BETWEEN THE RETAINING NUT AND THE PUMP ROD, SILICONE LUBRICATING OIL STORAGE MEANS, AND A SILICONE LUBRICATING FLUID SATURATED FIBER WASHER IN FLUID COMMUNICATION WITH THE LUBRICATING OIL STORAGE MEANS POSITIONED ABOUT THE PUMP ROD OUTWARDLY OF THE 